Influence of Seascape on Coastal Lagoon Fisheries: the Role of Habitat Mosaic in the Venice Lagoon

Abstract

Fisheries are a staple human activity supported by coastal lagoons. Together with water quality and trophic status, lagoon morphology is acknowledged as one of the main ecological drivers of fishery yields; however, the role of lagoon seascape structure is still poorly understood. This paper investigates how morphological variables, habitat distribution and seascape diversity and complexity affect yields of artisanal fishery performed with fyke nets in the Venice Lagoon (northern Adriatic Sea, Italy). Two spatial scales were considered in the analysis, with water quality parameters (temperature, salinity, dissolved oxygen, turbidity, water residence times, N, P and chlorophyll-a concentrations) being measured at a fine, fyke-net scale and morphological (average bottom elevation and sediment grain size) and habitat features (habitat proportion, diversity and complexity) being measured at a broader, seascape scale. Generalised linear mixed models were employed to model 8 years of nekton and green crab catches, disentangling the role of broad-scale morphology and seascape from that of fine-scale water quality. Broad-scale variables clearly influenced fishery target species. Among them, lagoon residents were associated with specific morphological and habitat characteristics, while marine migrants showed a stronger link with overall habitat diversity and complexity. This evidence emphasises how artisanal fishery in the Venice Lagoon relies on the conservation of morphological and habitat heterogeneity. Moreover, it highlights how habitat restoration performed at the seascape level should also be taken into account, in addition to controlling hydrology and water quality, when managing fishery resources in coastal lagoons.

Like little lagoons: the contribution of valli da pesca to the Ecosystem Services supply of the Venice Lagoon

“…On the other hand, while the fish migration and the recruitment processes taking place outside in the lagoon plays a fundamental role for sustaining fish lifecycle (Lanzoni et al 2021;Scapin et al 2022;Cavraro et al 2017) and the aquaculture ES in the valli da pesca, we could in turn affirm that the aquaculture ES in the valli da pesca could positively affect the regulating ES of lifecycle support in the entire lagoon. As happens for waterbirds, indeed, the persistency of suitable habitats in the valli da pesca depends on human maintenance, which in turn depend on economic resources that come from the provisioning ESs incomes.…”

Mediterranean Coastal Lagoons Review: Sites to Visit before Disappearance

“…On the one hand, if the opening is excessive, the environment becomes purely marine, rather than lagoonal, and this produces a loss of biodiversity [46]. However, when connectivity is lost or hindered by regulation of exchange, the loss is even greater; it is necessary to maintain the mosaic of lagoon ecosystems in order to conserve traditional fisheries [47].…”

Environmental DNA metabarcoding reveals spatial and seasonal patterns in the fish community in the Venice Lagoon

“…Although it was not one of the species that contributed most to the seasonality patterns when the SIMPER analysis was performed on the whole dataset, it resulted as a significant driver of the summerwinter dissimilarity when considering only the more freshwater associated northern site. Individuals of this species are known to leave rivers to migrate to the Sargasso Sea for reproduction (Cresci, 2020), and this species is temporarily abundant in the Venice Lagoon in fall, according to catches of fyke net surveys (Scapin et al, 2022). The MOSE infrastructure, according to official data, have been activated 33 times in the period of October 2020 -October 2022, exclusively in fall and winter (https://www.mosevenezia.eu/il-mose-in-funzione/#mvbtab_ 61894462f0019-1).…”